Residents remain apprehensive about a waterfront hotel in the 200 block of S. Union St., but city councilors green-lighted the project with a 6-0 vote Saturday.

The five-story, 120-room boutique hotel proposed by Carr City Centers — more commonly known as Washington-based Carr Hospitality — was in the works long before officials finished crafting the controversial waterfront redevelopment plan. That roadmap explicitly calls for at least two upscale lodges along the Potomac.

While Carr representatives have spent years working with city staff on the proposal, it marks the first major project outlined in the riverside plan to receive city council’s blessing.And that has drawn scrutiny from several local officials and residents, who wanted the undertaking delayed because they believe it sets the standard for future waterfront redevelopment.

But with assurances from city preservationist Al Cox and other planning officials that the final design would undergo more revisions before construction begins, city councilors overwhelmingly backed the project. Vice Mayor Allison Silberberg, who has criticized the waterfront plan, was out of town and did not cast a vote.

John Gosling, a former president of the Old Town Civic Association, offered perhaps the lightest criticism, pushing to see the proposed structure’s bulk reduced. The size and mass of the building have drawn opposition since the project was first unveiled.

Others had harsher words for Carr’s design.

“I grew up [near] San Quentin [State Prison in California],” said noted critic Townsend “Van” Van Fleet. “This building looks like a jail.”

Former city council candidate Bob Wood called the concept incomplete.

“What a depressing early end to our aspirations for a world-class waterfront,” he told city councilors.

Mayor Bill Euille, though, noted that many who spoke out against the project had fought the waterfront redevelopment plan tooth and nail since the very beginning. The blueprint, which was crafted after dozens of community meetings, sparked several unsuccessful court battles in recent years.

“The folks who have a problem, it’s not with this particular project … it’s [with] the master plan, and that’s already been decided,” he said.

One lawsuit stemming from the plan’s passage remains outstanding. That should be reason enough for officials to delay approval, argued Bert Ely, of Friends of the Alexandria Waterfront, a group that grew out of early resident-led opposition efforts.

Put on the spot about the litigation, which is before the Virginia Supreme Court, City Attorney Jim Banks said the lawsuit is similar to previous legal battles that have gone City Hall’s way. But, he warned, there’s no way of knowing what the commonwealth’s top judges will say or do.

“I must always qualify [my opinion] with, ‘I am not a great prognosticator,” Banks said. “I do not have a crystal ball.”

Despite the harsh words from critics, city councilors spent most of their discussion focusing on architectural issues, building materials and other practical concerns, like valet parking. They also tweaked the package of concessions that Carr is expected to give the city in exchange for development rights. Now that it has city council’s blessing, the project will head before the board of architectural review for final approval.

Along with the hotel, Carr’s plan calls for a restaurant, a 5,000-square-foot courtyard partially open to the public and an underground parking garage. Though the first of the major redevelopment projects slated for the waterfront, it is very likely not the last.

Officials said plans are moving ahead for the two Robinson Terminal warehouses as well as for the dilapidated Beachcomber building at the foot of Prince Street.